Method and apparatus for removing dust from a workpiece

ABSTRACT

A duct mechanism for directing a flow of air onto a working member of a power cutting tool generally includes a housing, a motor in the housing, a working member actuated by means of the motor and a shoe pivotally mounted relative to the working member and adapted to engage a workpiece. The duct mechanism includes an inlet portion mounted to the housing. The inlet portion receives a stream of air from the housing. An outlet portion is connected to the shoe for directing the stream of air onto the working member in a direction transverse to a line of action of the tool. At least one connecting portion connects the inlet portion and the outlet portion. The at least one connecting portion allows the outlet portion to pivot with the shoe relative to the inlet portion.

FIELD

The present invention relates to a method of removing dust from aworkpiece during operation thereon by a power tool, and relatesparticularly, but not exclusively, to a method of removing sawdust froma workpiece during sawing thereof by a jigsaw, and to a mechanism forcarrying out such a method.

BACKGROUND

Dust removal methods for jigsaws are well known, the two main methodsconsisting of blowing the dust out of the way of the jigsaw blade, orsucking the dust into a dust extraction device such as a vacuum cleaner.In either case, a blower or sucker is positioned immediately behind thejigsaw blade along the line of cutting action of the jigsaw. Inparticular, DE 2546527, DE 4316155, EP 0347631 and EP 0603552 alldisclose arrangements in which a dust inlet connected to a suctionsource is arranged adjacent the blade of a power saw. However, theseknown methods suffer from the drawback that if the blower or sucker ispositioned too close to the blade it becomes obtrusive, whereas if it istoo far away from the blade, it is insufficiently effective. Also, byblowing dust in a direction parallel to the line of action of the tool,dust may be blown onto the line to be cut by the tool, which may impedeits visibility and the subsequent cutting action.

SUMMARY

Preferred embodiments of the present invention seek to overcome theabove disadvantages of the prior art.

According to an aspect of the present invention, there is provided amethod of removing dust from a workpiece during operation thereon by apower cutting tool having a housing, a motor in the housing, and aworking member adapted to be actuated by means of said motor, the methodcomprising directing a stream of air onto said working member in adirection transverse to a line of action of the tool.

By directing a stream of pressurised gas onto a working member in adirection transverse to a line of action of the tool, this provides theadvantage that the outlet of the stream of pressurised gas can belocated very close to the working member, in order to be effective inblowing dust away from the working member, without the disadvantage ofthe outlet becoming obtrusive to a user of the tool. Furthermore, byblowing dust in a direction transverse to the line of action of thetool, the further advantage is provided that dust is blown away from theline to be cut, as opposed to onto that line.

The air may be air delivered by a fan used to cool said motor.

The method may further comprise the step of providing an inlet to asuction source adjacent said working member on a side thereof oppositeto the side from which said air is supplied.

This provides the advantage of further constraining airflow across theworking member of the tool, which minimises the tendency for dust blownaway from the working member to be scattered over a large area, therebyimproving effectiveness of dust removal.

According to another aspect of the present invention, there is provideda duct mechanism for directing flow of air onto a working member of apower cutting tool having a housing, a motor in the housing, a workingmember adapted to be actuated by means of said motor, and a shoepivotally mounted relative to the working member and adapted to engage aworkpiece, the mechanism comprising:

inlet means adapted to be mounted to the housing for receiving a streamof air from said housing;

outlet means adapted to be fixed in position relative to said shoe fordirecting said stream of air onto said working member in a directiontransverse to a line of action of the tool; and

at least one connecting portion for connecting said inlet means and saidoutlet means, wherein the or each said connecting portion is adapted toallow said outlet means to pivot with said shoe relative to said inletmeans.

At least one said connecting portion may be flexible.

At least one said connecting portion may comprise a first part integralwith one of said inlet or said outlet means, and a second part integralwith the other of said inlet means or said outlet means and at leastpartially received within said first part so as to be slidable relativeto said first part.

This provides the advantage of enabling the connecting portion to bemade from more durable material than in the case of a flexibleconnecting portion.

Said first and second parts may have mating curved surfaces in a planesubstantially perpendicular to the axis of pivotal movement of the shoerelative to the housing.

The mechanism may further comprise resilient mounting means for mountingthe outlet means to said shoe.

This provides the advantage of enabling the outlet means to be easilymounted to the shoe while enabling simple construction of the shoe,which in turn minimises the cost of production of a tool incorporatingthe mechanism.

According to a further aspect of the present invention, there isprovided a power cutting tool comprising a housing, a motor, an outputshaft adapted to execute reciprocating movement in response to saidmotor, and a duct mechanism as defined above.

The power tool may further comprise a fan for cooling said motor andadapted to supply flow of air to said inlet means.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention will now be described, by way ofexample only and not in any limitative sense, with reference to theaccompanying drawings, in which:

FIG. 1 is a front side perspective view of a jigsaw including a dustblowing device embodying the present invention;

FIG. 2 is a side perspective view of the jigsaw of FIG. 1 from theopposite side to that shown in FIG. 1;

FIG. 3 is a view corresponding to FIG. 2 but with the dust blowingdevice removed from the jigsaw;

FIG. 4 is a view corresponding to FIG. 3 but with the jigsaw supportshoe removed;

FIG. 5 is a schematic elevation view of one clamshell half of the jigsawof FIGS. 1 to 4;

FIG. 6 is a front view of the clamshell half of FIG. 5 taken along theline Y-Y;

FIG. 7 is a view corresponding to FIG. 5 but showing the internalcomponents of the jigsaw;

FIG. 8 is a perspective view from above and one side of the jigsaw shoewith the dust blowing device in situ;

FIG. 9 is a plan view of the jigsaw shoe of FIG. 8 but with the dustblowing device removed;

FIG. 10 is a sectional view along the line X-X of FIG. 9;

FIG. 11 is a sectional view along the line B-B of FIG. 9;

FIG. 12 is a plan view from one side of the bridge element of the dustblowing device;

FIG. 13 is a view along the line A-A in FIG. 12;

FIG. 14 is a plan view from above of the bridge element of FIG. 12;

FIG. 15 is a view along the line C-C of FIG. 14;

FIG. 16 is an end view of the outer dust blowing opening of the bridgeelement of FIG. 12; and

FIG. 17 is an end view of the opening of the connector piece which matesthe bridge element of FIG. 12 with the jigsaw of FIGS. 1 to 4.

DETAILED DESCRIPTION

Referring to FIGS. 1 to 4, a jigsaw 2 has a housing in the form of aclamshell formed from two halves 4, 6. The jigsaw 2 is formed so as toprovide a handle portion 8 to be gripped by a user, and defines a region10 where a trigger (FIG. 7) is formed so that the user can activate thejigsaw 2 in order to cut a workpiece (not shown).

Power is supplied to the jigsaw 2 via power cord 12 (FIG. 3). A bladeguard retaining mechanism 14 is provided at the front portion of thejigsaw.

Referring now to FIGS. 4 to 7, it can be seen that the lower portions ofthe two clamshell halves 4, 6 define a lower portion 16 which provides aduct 18 through which air may be blown. As best shown in FIG. 5, theduct 18 is formed by channelling in the clamshell half 6 so that acontinuous channel 20 is formed to enable the duct 18 to communicatewith jigsaw fan 22 (FIG. 7) which also serves, as will be appreciated bypersons skilled in the art, to cool the jigsaw motor (FIG. 7) during useof the jigsaw.

When the user actuates the trigger 10 (FIG. 7), electrical power issupplied via power cable 12 to motor 24, which in turn rotates itsoutput shaft 26 as shown in FIG. 7. The output shaft 26 has a splineddrive 28 at the distal end thereof, the drive 28 communicating with agear wheel 30. The gear wheel 30 has an eccentric 32 mounted thereonwhich couples, via a scotch yoke mechanism which will be familiar topersons skilled in the art, with a reciprocating drive shaft 34 whichhas at its lower end a blade clamping mechanism 36 for coupling a jigsawblade (not shown) to the drive shaft 34. In this way, rotation of theoutput shaft 26 causes reciprocating motion of the drive shaft 34 andthe jigsaw blade attached to the drive shaft 34, in the direction ofarrow A in FIG. 7.

At the same time, actuation of the motor 24 causes rotation of the fan22 which causes a stream of air to be forced from the duct 18 in orderto cool the motor 24. This stream of air is also utilised to blow dust,produced during the cutting operation of the jigsaw, from a workpiecebeing cut, as will be described in greater detail below.

Referring now to FIGS. 8 to 17, a jigsaw support shoe 38, which ispreferably stamped from a single piece of metal, is provided with aconcave support surface 40. The concave support surface 40 is arrangedto mate with the lower portion 16 of the jigsaw body 2 such thatcoupling of the convex profile of the lower portion 16 with the concaveprofile of the support surface 40 enables the support shoe 38 to bepivoted relative to the jigsaw body 2 to allow for bevel cutting.

The jigsaw support shoe 38 receives a bridge member 42 which clips intoa corner of the support shoe 38 to define a conduit for transporting airfrom the duct 18 to the position at which the jigsaw blade (not shown)cuts through the workpiece.

This is achieved by the bridge member 42 coupling with a connector piece44 situated between the output of the duct 18 and the input portion 46of the bridge member 42, the bridge member 42 and connector piece 44being separate elements. The bridge member 42 is hollow so as to providea channel through which air may be vented between the jigsaw body lowerportion 16 and that piece of the workpiece being cut by the jigsawblade.

As shown most clearly in FIGS. 8 and 13, the connector piece 44 coupleswith the input portion 46 of bridge member 42. The connector piece 44has an input port 48 of generally circular cross-section which protrudesinto the external portion of the duct 18 of the lower portion 16 ofjigsaw body 2, for example as seen in FIGS. 1 and 2. The input port 48of connector piece 44 is of generally circular cross-section so as toallow pivoting of the support shoe 38 relative to the jigsaw body 2, andthe connector piece 44 also serves to rotate the flow of air exitingduct 18 through approximately 90° so that it can pass to the inputportion 46 of bridge member 42 to be directed towards the jigsaw blade.

Air which has entered input port 48 of the connector piece 44 and thenbeen rotated through 90° enters the bridge member 42 via its inputportion 46. Because of the hollow internal structure of bridge member42, air passes through main extending arm 50 of the bridge member 42from where it is ejected via exit port 52 (FIG. 15) so as to strike thejigsaw blade from one side thereof.

The operation of the jigsaw shown in the Figures will now be described.

In order to remove dust from that part of a workpiece being cut by thesaw, air is directed from exit port 52 onto a side of the saw blade. Theair is directed in a direction transverse to the line of action of thesaw, as a result of which it can be located close to the blade so thatit is effective without being obtrusive to a user of the jigsaw. At thesame time, an inlet to a suction tube 54 may be arranged on the oppositeside of the jigsaw blade to bridge member 42 to further constrain theflow of air. The suction tube 54 can then be connected to a source ofsuction 56 such as a vacuum cleaner (not shown).

It will be appreciated by persons skilled in the art that the aboveembodiment has been described by way of example only, and not in anylimitative sense, and that various alterations and modifications arepossible without departure from the scope of the invention as defined bythe appended claims. For example, the bridge member 42 and connectorpiece 44 may be formed as a single unit, and the bridge member 42 may beprovided on the opposite side of the jigsaw blade to that shown in FIG.8.

1. A dust mechanism for directing a flow of air onto a working member ofa power cutting tool having a housing, a motor in the housing, a workingmember actuated by said motor and a shoe pivotally mounted relative tothe working member and adapted to engage a workpiece, the dust mechanismcomprising: a connector piece having an input port that is connected toa duct in the housing, wherein said input port receives the flow of airfrom the housing in a direction generally in line with an axis ofpivotal movement of the shoe relative to the housing and wherein saidconnector piece is operable to rotate relative to said duct in thehousing when the shoe pivots relative to the housing and while saidconnector piece is fluidly connected to said duct; and a bridge memberfluidly connected to said connector piece and removably connected to atop surface of the shoe opposite a surface adapted to engage theworkpiece, wherein said bridge member defines a generally hollow channelthat terminates at an exit port from which the flow of air from saidduct in the housing is directed onto the working member in a directiontransverse to a line of action of the tool.
 2. The dust mechanism ofclaim 1 wherein said connector piece and said bridge member are separatepieces fluidly connected and wherein said connector piece is moveablerelative to said bridge member.
 3. The dust mechanism of claim 2 whereinsaid connector piece and said bridge member have mating curved surfacesthat permit said connector piece and said bridge member rotate relativeto one another.
 4. The dust mechanism of claim 1 further comprising aresilient connector piece that mounts said bridge member to said surfaceof the shoe.
 5. The dust mechanism of claim 1 further comprising anoutput shaft that executes a reciprocating movement in response to saidmotor.
 6. The dust mechanism of claim 5 further comprising a fan forcooling said motor and for supplying the flow of air to said connectorpiece of the dust mechanism.
 7. The dust mechanism of claim 1 furthercomprising an inlet to a suction source disposed adjacent to the workingmember and on a side thereof opposite to a side from which the flow ofair is supplied by said bridge member.
 8. The dust mechanism of claim 1wherein said duct extends in a direction through said housing that isgenerally parallel to said axis of pivotal movement of the shoe relativeto the housing.
 9. The dust mechanism of claim 8 wherein said duct isopen to a front side of the power cutting tool.
 10. A power cutting toolfor cutting a workpiece, the cutting tool comprising: a housing, and amotor contained in said housing; a duct formed in said housing, whereinsaid duct is open to a front side of the power cutting tool and whereinsaid duct connects to an airflow pathway in said housing through which afan connected to said motor establishes a flow of air; a working memberactuated by said motor; a shoe pivotally mounted to said housingrelative to the working member, said shoe adapted to engage theworkpiece; and a dust mechanism including a connector piece fluidlyconnected to a bridge member, wherein said connector piece includes aninput port that is connected to said duct in said housing, wherein saidconnector piece receives said flow of air from said duct in a directiongenerally in line with an axis of pivotal movement of said shoe relativeto said housing, wherein said connector piece is operable to rotaterelative to said duct in said housing when said shoe pivots relative tosaid housing and while said connector piece is fluidly connected to saidduct, wherein said bridge member is removably connected to a top surfaceof said shoe opposite a surface adapted to engage the workpiece, andwherein said bridge member defines a generally hollow channel thatterminates at an exit port from which the flow of air from said duct insaid housing and through said connector piece is directed onto saidworking member in a direction transverse to said line of action of thepower cutting tool.
 11. The power cutting tool of claim 10, wherein saidconnector piece and said bridge member are separate pieces fluidlyconnected and wherein said connector piece is moveable relative to saidbridge member.
 12. The power cutting tool of claim 10 further comprisinga resilient connector piece that mounts said bridge member to saidsurface of the shoe opposite said surface that engages the workpiece.13. The power cutting tool of claim 10 further comprising an inlet to asuction source disposed adjacent to said working member and on a sidethereof opposite to a side from which the flow of air is supplied bysaid bridge member.